One way to spice up new and existing zones. World Tomes:

[BruceyBruceyBangBang]

Look, it's a nice idea. Maybe better for some temp who is running out of simple tasks to do at the development offices in Japan could write these up. I say this because I feel like this is the only person who could have the time to get this done with all the crap they have to work on ATM. No offense.

I'm going to have to commend you on your commitment and I think that your task of pushing the game to your own specific threshold into what immerses you is a pretty ballsy undertaking! Your next task should be to get a clue and remember one simple fact: your quest for immersion is futile being that it's subjective. So, let's try to stay away from that for a little while... cause you can still come up with some pretty good ideas. Which goes to my next thing...

Now, to asses the actual content of this OP rather than venting on your opening sentence, I'd be into it. I love the story of FFXIV so far. There were many class quests that stuck out for me, one being the MIN quests surprisingly, that was pretty heavy with Ul'dah's past and it's ancient sister city. It really kept you interested and was read very humorously. I won't give anything important away with that... just an example. As long as the writing captures the spirit of those few fun class quests, as far as story goes, then I'd think you'd have a hit.